A. Notwithstanding the other provisions of this article, the Commissioner of Highways or other authority having jurisdiction over highways may decrease the speed limits set forth in § 46.2-870 and may increase or decrease the speed limits set forth in §§ 46.2-873 through 46.2-875 on any highway under its jurisdiction; and may establish differentiated speed limits for daytime and nighttime by decreasing for nighttime driving the speed limits set forth in § 46.2-870 and by increasing for daytime or decreasing for nighttime the speed limits set forth in §§ 46.2-873 through 46.2-875 on any highway under his jurisdiction. Such increased or decreased speed limits and such differentiated speed limits for daytime and nighttime driving shall be effective only when prescribed after a traffic engineering investigation and when indicated on the highway by signs. It shall be unlawful to operate any motor vehicle in excess of speed limits established and posted as provided in this section. The increased or decreased speed limits over highways under the control of the Commissioner of Highways shall be effective only when prescribed in writing by the Commissioner of Highways and kept on file in the Central Office of the Department of Transportation. Whenever the speed limit on any highway has been increased or decreased or a differential speed limit has been established and such speed limit is properly posted, there shall be a rebuttable presumption that the change in speed was properly established in accordance with the provisions of this section.

B. Notwithstanding any other provision of this article, including the provisions of subsection A, the governing body of any town located entirely within the confines of a United States military base may by ordinance reduce the speed limit to less than 25 miles per hour on any highway within its boundaries, provided such reduced speed limit is indicated by lawfully placed signs.

Code 1950, § 46-212; 1950, p. 881; 1952, c. 666; 1954, c. 244; 1956, c. 364; 1958, c. 541, § 46.1-193; 1960, c. 153; 1962, c. 307; 1964, cc. 118, 408; 1966, c. 85; 1968, c. 641; 1972, cc. 89, 546, 553, 608; 1974, c. 528; 1977, c. 577; 1978, c. 605; 1980, c. 347; 1989, c. 727; 1990, c. 779; 1993, c. 98; 2013, c. 303.